Dredging-machine



(No Model.)

J. R. GROOKETT.'

DREDGING MACHINE.

No. 362,877. Patented May10 1887.

W TJVESSES I N VEJV' TOR Attorneys NITE STATES JOHN RICHARDSON GROOKETT, OF FLATONIA, TEXAS.

DREDGlNG MACHINE.

SPECIFICATION forming part of Letters Patent No. 362,877, dated May 10, 1887.

Application filed February 7, 1887. Serial No. 226.816.

To all whom, it may concern:

Be it known that I, JOHN RICHARD SON GRooKnrr, a citizen of the United States, and a resident of Flatonia, in the county of Fayette and State of Texas, have invented certain new and useful Improvements in Dredging- Machines; and I do declare the following to be a full, clear, and exact description of the inven tion, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters or figures of reference marked thereon, which form a part of this specification.

Figure 1 of the drawings is a representation of a side elevation of a boat equipped with my dredger. Fig. 2 is a bottom plan view of the same. Fig. 3 is a vertical transverse section on the line 00 :0, Fig. 1.

My invention relates to dredging-machines designed for use in connection with boats or Coffer-dams for removing sand-bars and similar obstructions in the beds of harbors or in streams by loosening the sand or the like, so that it will be suspended in the water and carried off by the natural or created current; and the invention consists in the construction and novel combination of parts, as hereinafter described and claimed.

In the drawings I have confined the illustration of the application of the invention to a boat, which will be sufficient to enable persons skilled in the art to which the invehtion appertains to apply the invention to a cofferdam as well.

Referring by letter to the accompanying drawings, A designates a boat, which is provided along the lower edge of its keel B with a convex shield, 0, made of planks or other suitable material, said shield 0 being secured in place in any secure and desirable manner. At the bow and the stern of the boat I provide hangers D and E, the lower ends of which project below the shield G a proper distance. Near their lower ends the hangers D E are provided with bearings, in which the journals F G of the shaft H are supported.

The shaft H is provided with a spiral screw, I, which is secured thereto or made integral therewith, as may be preferred, the screw extending from end to end of the shaft.

(No model.)

The projecting end of the journal F is provided with a crank, f, which is connected to the pitman of an engine on board the boat.

In operation the machine or the boat is to be anchored over the sand-bar, and sufficient ballast must be employed to sink the boat to the proper depth to permit the screw toloosen the sand or mud when driven by the engine. The screw, when operated,loosens the sand or mud, and also creates a current in the water, which induced current carries the sand and mud away from the bar into deeper water, thereby removing the sand-bar or similar obstruction.

When applied to a coflerdam, the screw is located at one end of the dam. The convex shield on the keel or bottom of the boat is for concentrating the currcnt,and thereby giving it greater force and effect. The coffer-dam should be built at the head of the Sandbar, and properly ballasted and anchored, and supported as often as may be necessary to prevent it from vibrating. The preferable plan of employing the boat is to constructa line of boats over the bar and cause the first to drive the sand, &c.,to the second, and thus on throughout the line of boats. As the channel created by the screw deepens,more ballast should be added to sink the boat,to permit its operation to be effective, until the required depth is attained, after which the boats are moved sidewise until the desired width has been excavated, loosened, or dredged.

Having described this invention, what I claim, and desire to secure by Letters Patent, 1s-

The combination, with a boat or the like provided with depending hangers at its bow and stern, of the shaft journaled in said hangers and provided with a spiral screw extending throughout its length, substantially as specified.

In testimony whereof I affix my signature in presence of two witnesses.

JOHN RICHARDSON CROOKE'IY'I.

\Vitnesses:

J. LANE, It. L. SIMMONs. 

